Stage 1 Immobilizer

Immobilizer stage 1






Arrangements of components for immobilizer stage 1

Immobilizer stage 1 (vehicles as of 01/94)
As of 01/94, the pneumatic control unit (A37/2 - A37/5) will have an electrical output (pin 7 on plug 1) to actuate the immobilizer relay (K38) for the function of the immobilizer.

If the vehicle is unlocked from outside via one of the three operating points (convenience switch SN1 operates), the immobilizer output is switched to ground. After the ignition is switched on, the immobilizer relay (K38) picks up and closes the starter current circuit. The vehicle can be started. If the vehicle is locked from outside via one of the three operating points (convenience switch SN2 operates), ground actuation for the immobilizer relay (K38) is open-circuited via the immobilizer output.

The starter current circuit is open-circuited as a result and the vehicle cannot be started.


NOTE: On vehicles as of 01/94 with infrared remote control for the central locking system (IFZ), the immobilizer relay (K38) is not actuated via the pneumatic control unit (A37/2 - A37/1), but via the infrared remote control unit for the central locking system (N54).

Notes on repair
If the immobilizer relay (K38) fails, disconnect the appropriate lines in the area of the A pillar and install a new relay. For the installation point, refer to installation instructions (connection in accordance with the wiring diagram).